PMID-4598035[0] Operant conditioning of single-unit response patterns in visual cortex.
- In cat V1 -- suprising, this is usually considered to be sensory.
- implanted bilater tripolar stimulating electrodes aimed at the lateral hypothalamus. These were tested for self-stimulation, and preferred locations/currents were selected for optimal ICS reinforcement.
- 200 bar presses in 8 minute test.
- Anesthetized, immobilized, head-restrained, contact-lens focused cats.
- Back projected stimuli onto a screen 50 cm from eye ; dot, bar, or small spot was effective in triggering patterned response, as with many of these studies.
- For conditioning: set a threshold at the third quartile (1/4 of trials exceeded threshold); comparator circuit counted the number of spikes during stimulus presentation, and if threshold was exceeded, reinforcing ICS was delivered.
- Reinforcing ICS started 300ms after visual stimulus and lasted 500ms.
- Conditioning was deemed successful if the mean trial firing rate for the last 50 conditioned trials had a mean firing rate > 30% larger than the first 50 control trials.
- While recording some cells, ICS reinforcement was delivered at random as control.
- Conditioning produced changes within stimulus presentation but not outside.
- They consider the use of an immobilized subject is a pro -- better control, rules out alternative explanations based on motor feedback.
____References____
[0] Shinkman PG, Bruce CJ, Pfingst BE, Operant conditioning of single-unit response patterns in visual cortex.Science 184:4142, 1194-6 (1974 Jun 14) |
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